Abstract 18843: Confounding Effects of Right Ventricular Outflow Tract Obstruction on the Impact of Pulmonary Regurgitation on Right Ventricular Size and Function in Patients After Repair of Tetralogy of Fallot
Introduction: In animal studies, it was demonstrated that combined pulmonary regurgitation (PR) + right ventricular outflow tract (RVOT) obstruction (RVOTO) may act as a potential protective factor limiting negative impact of PR on right ventricular (RV) size and myocardial contractility. The influence of combined PR+RVOTO on RV size and function in adult population after repair of tetralogy of Fallot (TOF) has not been formally studied. It remains unclear whether RVOTO should be considered in assessing the influence of PR on RV volumes.
Hypothesis: We hypothesized that in patients with similar levels of PR, RV volumes and function are better preserved in the presence of RVOTO. To evaluate these issues we have decided to perform the current study.
Methods: Consecutive individuals with significant PR [PR fraction (PRF)>=20%] after TOF repair who underwent cardiac magnetic resonance (CMR) were included. Patients with additional haemodynamic abnormalities (residual ventricular septal defect, extracardiac shunt and/or more than mild regurgitation at a valve other than the pulmonary valve) were excluded.
Results: During the study period 90 patients after TOF repair underwent CMR. However, 48 patients met exclusion criteria. Significant differences between patients with combined PR+RVOTO (n=33) and isolated PR (n=9) were observed in RV end-diastolic volume, RV end-systolic volume and RV ejection fraction (RVEF)despite similar degree of PR measured both as PRF and PR volume (PRV) (Table). Both, PR and peak RVOT gradient were independent predictors of RV size. There were no differences between two groups in clinical status according to New York Heart Association class.
Conclusions: Patients with combined PR+RVOTO have smaller RV volumes and higher RVEF when compared to patients with isolated PR. The confounding effect of RVOTO on RV size and function needs to be taken into consideration in CMR studies evaluating patients after TOF repair.
- © 2010 by American Heart Association, Inc.